The invention is concerned with a device to produce internal circulation in hot water tanks and hot water heaters.
In large domestic hot water tanks, it is common to convey water from the upper part to the lower part of the tank by means of a circulation pump. This ensures that the cold water in the bottom part of the tank will also be heated. In this manner, the heat content of the storage tank can be considerably increased. The disadvantage of this method is that conventional circulation pumps must be used. These have high electricity consumption, have a tendency to seize, and lead to mixing of the various temperature zones irrespective of the temperature profile within the tank. If a large portion of the stored water is still cold, such mixing leads to an unacceptably large temperature drop in the upper zone of the tank, which feeds the hot water system.